More recent studies from us and others have shown that IL-4 responsive CD4+ T cells [28] or signalling through the STAT-6 pathway in these cells is not needed for worm expulsion. Indeed, IL-4 receptor expression by non-bone marrowderived cells is required to expel N. brasiliensis [44]. However, type 2 immunity is controlled by IL-4/IL-13 expression in haematopoetic non-eosinophil cells of the innate Hypericin site immune system [45]. This is consistent with the findings in our present study, as infected mice deficient in 1676428 IL-4Ra expression on all T cell subpopulations showed impaired TH2 ASP-015K web responses but still presentedIL-13 production in the mesenteric lymph nodes, able to respond with goblet cell hyperplasia and controlling infection. In contrast, global IL-4Ra mice could not respond to IL-4 or IL-13, hence were impaired in effective worm expulsion. IL-4 is also known to suppress TH17 development in a STAT-6 dependent manner [46] with IL-4Ra2/ 2 mice producing increased levels 15481974 of IL-17 in an allergic asthma model [47]. We showed that IL-17 production is increased in IL4Ra2/2 mice in response to N. brasiliensis but remains comparable with control mice in iLckcreIL-4Ra2/lox mice. This suggests that the suppression of IL-17 is independent of IL-4Ra signalling on T cells. Recent research showed that infection with different nematodes induces an increased smooth muscle cell driven intestinal contractility in wild-type mice [9,15,21,33]. This is believed to be instrumental for the weep and sweep process to diminish the worm from the gut lumen. It has been shown that IL-4 and IL-13 promote acetylcholine-induced intestinal hypercontractility andIL-4Ra-Mediated Intestinal Hypercontractilitythat IL-4 can directly enhance smooth muscle cell contractility without influencing the enteric nervous system [9]. Moreover, responses to acetylcholine were attenuated in STAT62/2 mice, which suggest at least a partial dependence of smooth muscle cell hypercontractility on the IL-4/IL-13/STAT-6 pathway [9]. This was recently substantiated by us as the jejunum of N. brasiliensisinfected smooth muscle cell-specific IL-4Ra deficient mice, and more drastically N. brasiliensis-infected global IL-4Ra2/2 mice showed abrogated contractility in response to acetylcholine stimulation [21]. Little is known about the possible role of other cell types in worm-induced intestinal smooth muscle cell hypercontraction. However, it has been shown that macrophages play a key role in negatively regulating Trichinella spiralis induced hypercontractility, which is in-part mediated through macrophage M-CSF production [48,49]. In this study, we showed that IL-4Raresponsive T cells are needed for efficient intestinal smooth muscle cell contraction. Absence of IL-4-responsive T cells resulted in 
impaired IL-4 production from CD4+ T cells in the mesenteric lymph node and strikingly reduced IL-4 and IL-13 production in the intestine, which explains impaired IL-4/IL-13-mediated smooth muscle cell hypercontractility. Interestingly, mice were still able to expel the worm despite abrogated intestinal hypercontractility. In conclusion, this study highlights the contributing role of IL-4promoted TH2 cells with their major importance not in worm expulsion but in controlling IL-4/IL-13-induced intestinal hypercontractility. Although this is a major host physiological response to helminthes, it seems that smooth muscle hypercontractility induced by acetylcholine is not needed for efficient worm expulsion during pr.More recent studies from us and others have shown that IL-4 responsive CD4+ T cells [28] or signalling through the STAT-6 pathway in these cells is not needed for worm expulsion. Indeed, 
IL-4 receptor expression by non-bone marrowderived cells is required to expel N. brasiliensis [44]. However, type 2 immunity is controlled by IL-4/IL-13 expression in haematopoetic non-eosinophil cells of the innate immune system [45]. This is consistent with the findings in our present study, as infected mice deficient in 1676428 IL-4Ra expression on all T cell subpopulations showed impaired TH2 responses but still presentedIL-13 production in the mesenteric lymph nodes, able to respond with goblet cell hyperplasia and controlling infection. In contrast, global IL-4Ra mice could not respond to IL-4 or IL-13, hence were impaired in effective worm expulsion. IL-4 is also known to suppress TH17 development in a STAT-6 dependent manner [46] with IL-4Ra2/ 2 mice producing increased levels 15481974 of IL-17 in an allergic asthma model [47]. We showed that IL-17 production is increased in IL4Ra2/2 mice in response to N. brasiliensis but remains comparable with control mice in iLckcreIL-4Ra2/lox mice. This suggests that the suppression of IL-17 is independent of IL-4Ra signalling on T cells. Recent research showed that infection with different nematodes induces an increased smooth muscle cell driven intestinal contractility in wild-type mice [9,15,21,33]. This is believed to be instrumental for the weep and sweep process to diminish the worm from the gut lumen. It has been shown that IL-4 and IL-13 promote acetylcholine-induced intestinal hypercontractility andIL-4Ra-Mediated Intestinal Hypercontractilitythat IL-4 can directly enhance smooth muscle cell contractility without influencing the enteric nervous system [9]. Moreover, responses to acetylcholine were attenuated in STAT62/2 mice, which suggest at least a partial dependence of smooth muscle cell hypercontractility on the IL-4/IL-13/STAT-6 pathway [9]. This was recently substantiated by us as the jejunum of N. brasiliensisinfected smooth muscle cell-specific IL-4Ra deficient mice, and more drastically N. brasiliensis-infected global IL-4Ra2/2 mice showed abrogated contractility in response to acetylcholine stimulation [21]. Little is known about the possible role of other cell types in worm-induced intestinal smooth muscle cell hypercontraction. However, it has been shown that macrophages play a key role in negatively regulating Trichinella spiralis induced hypercontractility, which is in-part mediated through macrophage M-CSF production [48,49]. In this study, we showed that IL-4Raresponsive T cells are needed for efficient intestinal smooth muscle cell contraction. Absence of IL-4-responsive T cells resulted in impaired IL-4 production from CD4+ T cells in the mesenteric lymph node and strikingly reduced IL-4 and IL-13 production in the intestine, which explains impaired IL-4/IL-13-mediated smooth muscle cell hypercontractility. Interestingly, mice were still able to expel the worm despite abrogated intestinal hypercontractility. In conclusion, this study highlights the contributing role of IL-4promoted TH2 cells with their major importance not in worm expulsion but in controlling IL-4/IL-13-induced intestinal hypercontractility. Although this is a major host physiological response to helminthes, it seems that smooth muscle hypercontractility induced by acetylcholine is not needed for efficient worm expulsion during pr.
